Trunion liner and seal for rotary mills

ABSTRACT

Apparatus of the ball or tube mill type for reducing and pulverizing material. A hollow shell containing the material to be reduced, such as ore, is rotatably supported by means of end positioned trunnions. Infeed material is introduced into the shell by means of a flexible feed spout extending through an opening in one of the trunnions. A trunnion liner and seal comprising an inflatable tire mounted on a wheel rim is positioned around the feed spout in the trunnion opening. The tire is inflated to expand its outer periphery into deformable sealing relationship with the inner surface of the trunnion.

United States Patent Kastrinos July 17, 1973 [54] TRUNION LINER AND SEAL FOR ROTARY 3,047,242 7/1962 Genier 241/171 MILLS I Primary Examiner-Donald G. Kelly [75] Inventor. Arthur Kastrinos, Lima, Peru Atmmey nehr Hohbach ct 21L [73] Assignee: Marcona Corporation, San

Francisco, Calif. [57] ABSTRACT [22] Filed; O t, 26, 1971 Apparatus of the ball or tube mill type for reducing and 21 Appl. No.: 192,024

pulverizing material. A hollow shell containing the material to be reduced, such as ore, is rotatably supported by means of end positioned trunnions. lnfeed material is introduced into the shell by means of a flexible feed spout extending through an opening in one of the trunnions. A trunnion liner and seal comprising an inflatable tire mounted on a wheel rim is positioned around the feed spout in the trunnion opening. The tire is inflated to expand its outer periphery into deformable sealing relationship with the inner surface of the trunmon.

10 Claims, 2 Drawing Figures [52] US. Cl. 241/179 [51] Int. Cl..l B02c 17/18 [58]" Field of Search 241/171, 176, DIG. 30,

[56] References Cited UNITED STATES PATENTS 1,607,828 11/1926 Holthoff 241/DlG. 30 3,401,893 9/1968 Reynolds 241/171 Patented July 17, 1973 .2 Sheets-Sheet l INVENTOR. Aer/1025. (mire/-05 L V34; m

Attorneys TRUNION LINER AND SEAL FOR ROTARY MILLS BACKGROUND OF THE INVENTION This invention relates in general to improvements in apparatus of the ball or tube mill type for pulverizing and reducing material such as ore and the like. In par ticular the invention relates to improvements in the material feed structure for mills of the type described.

Existing ball and tube mills reduce and pulverize material such as ore by rotating a shell for impacting the contained material with a number of steel balls, pebbles or rods. The shell is rotatably supported through end positioned trunnions riding in pillow blocks. The ore is directed into the shell by means of a feed spout which extends through an opening in one of the trunnions. A rigid metal liner is mounted within the opening to rotate with the trunnion for directing ore from the spout into the mill. The liner may be provided with spiral internal ridges and other means for restraining ore in the mill from falling back through the input opening. As the trunnion rotates under heavy load it will tend to distort relative to the liner creating a degree of slip or slide between the trunnion and liner, accompanied by a working of their confronting surfaces, so that openings are formed sufficiently large to admit small amounts of sults, and this leads to wear and failure of the trunnion bearing from the grinding action of the ore which is racing between the liner and trunnion. Also, the aforementioned distortion of the trunnion is rigidly transmitted to the liner where it is fastened to the trunnion, and this ultimately leads to failure of the fastening means, and in particular to the shearing of the fastening bolts. Where the foregoing conditions progress to the extent that ore leaks from the end of the mill and works down into the trunnion bearing itself, then this leads to total failure of the bearing. These problems have not only been costly in terms of labor, parts and down-time for correction and replacement, but they have limited the size of practical rotary mills. Thus, the size of conven tional mills is limited because large overhead cranes are required to lift the elements for bearing replacement. Also, this operation is time consuming in that it normally takes on the order of several hours to complete.

Accordingly, the need had been recognized for improved reducing and pulverizing apparatus of the ball or tube mill type, and method of installation, which will obviate the aforementioned problems encountered with existing equipment.

OBJECTS AND SUMMARY OF THE INVENTION It is a general object of the invention to provide improvements in rotary mill apparatus thereof.

It is another object of the invention to provide an improved material in-feed structure for reducing and pulverizing apparatus of the ball or tube mill type.

Another object is to provide apparatus forming an effective sealing means between the material feed spout and associated support trunnion on a ball or tube mill type pulverizier to obviate the problems associated with material leakage from the mill through the trunnion and to make practical the construction of a mill size much larger than is presently feasible.

The invention provides a rotary mill having a hollow shell containing a plurality of impacting elements for reducing and pulverizing material progressing through the shell. The shell has a material in-feed opening at one end, and is rotatably supported at opposite ends by hearing means. The bearing means at the in-feed end comprises a hollow trunnion and associated bushing, with feeder conduit means having a discharge end extending concentrically through the trunnion and in discharge relationship with the shell in-feed opening. Deformable sealing means is provided to prevent discharge of material from between the trunnion and feeder conduit means. The sealing means comprises an elastomeric annular member defining a hollow annular chamber and positioned between the trunnion and feeder conduit means. Means are provided to confine a charge of gas under pressure within the chamber to expand the annular member into sealing relationship with the trunnion. The annular member has a central opening positioned in close-spaced relationship around the conduit means and adopted for relative rotation thereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational axial view, partially in section and partially in phantom, of a reducing and pulverizing mill constructed in accordance with the present invention; and

FIG. 2 is a fragmentary axial section view to an enlarged scale of the trunnion liner and seal at the material in-feed end of the apparatus of FIG. 1, taken along the lines 2-2 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT V In the drawings FIG. 1 illustrates a preferred embodiment of the invention providing reducing and pulverizing mill 10 of the ball or tube mill type. Mill 10 includes a hollow shell 12 mounted for rotation about a horizontally disposed, longitudinal axis by means of opposed trunnion bearing assemblies 14, 16. Shell 12 is cylindrical in configuration and is of a large capacity adapted to contain a plurality of impacting elements such as steel balls, pebbles, or rods for reducing the product material, such as ore, by impact and attrition.

The material to be reduced is introduced into one end of the shell through infeed opening 18 by means of feeder conduit 20 comprising a flexible spout, preferably a rubber hose, which in turn receives material from a suitable feed conveyor or hopper, not shown. The material advances axially through the rotating shell as it is progressively reduced and then passes out of the mill through discharge trommel assembly 22, which may be of the overflow discharge type.

The shell is rotated at a suitable speed on the order of 14 rpm by means of a mill drive, not shown, connected through an extension of discharge trommel assembly 22.

FIG. 2 illustrates details of trunnion bearing assembly 14 at the infeed end of the mill. The trunnion bearing assembly comprises a trunnion 24 extending outwardly from an integral end plate 26 forming the end closure for the shell. The inside surface of the shell is lined with a suitable non-metalic layer including an annular rubber liner 28 mounted against end plate 26. Rotatable support for the trunnion 24 is provided by a half-sleeve bushing 30 which in turn is supported on base member 32. The base member is mounted above a sole plate assembly 34 supported on a suitable structure such as concrete foundation 36. A groove 38 is formed around the outer surface of trunnion 24 to ride upon bushing 30. Suitable oil distributor means, not shown, is provided to feed lubricating oil into the groove of the rotating trunnion. A protective housing 39 is mounted above the elements of the trunnion assembly. (FIG. 1.).

Means 24 is provided for forming a liner and] deformable seal between the trunnion and feed spout. A radially expandable elastome'ric annular member 40 of a solid material such as rubber is mounted about a rigid annular rim 42 to define a hollow annular chamber 44. A releasable check valve 45 is provided to control the amount of pressure of the gas volume within the chamber. With the chamber pressurized, the outwardly facing cylindrical surface 46 of the annular member expands into tight-fitting sealing relationship with inner surface 48 of the central opening formed in the trunmon.

In the illustrated embodiment a large diameter rubber tire and wheel unit of the type used for heavy duty construction vehicles is modified in accordance with the invention for installation as the liner and deformable seal for the rotary mill. The tire forms annular member 40 and it seats within the outwardly facing annular recess 49 of the wheel rim. The tire size is selected so that its outwardly facing cylindrical surface has a diameter commensurate generally with the inner surface of the trunnion. The outer edge of the tire is turned down to form a shoulder 50 which seats against a retaining shoulder 52 provided within the trunnion opening. The tire is locked into seating relationship against shoulder 52 by means of a retainer ring 54 held in place by a plurality of retainer rods 56 extending inwardly from annular plate 58 which in turn is bolted to the end of the trunnion. A plastic lining 60 is secured to the liner surface of the trunnion between the tire 40 and plate 58.

The discharge end 62 of feeder spout extends through the central opening of wheel rim 42 into discharge relationship with the infeed opening of the mill. A sealing ring 64, which may be formed of a plastic material, is fastened by means such as bolts to the mounting flange 66 on the wheel rim. The inner diameter of ring 64 provides means forming an inner circular port which is in close-spaced relationship with the outer surface of the feeder conduit and affords relative rotational movement therebetween while functioning to prevent ore from leaking between the wheel rim and feeder spout. An annular liner 68 of an elastomeric material such as rubber is bonded within the wheel rim and is formed with an inner frustoconical surface concave with respect to the infeed opening of the mill. Additionally, an annular liner 70 of an elastomeric material such as rubber is bonded to the tire side surface facing the shell.

Sealing means 24 is installed within trunnion bearing assembly 14 as follows. Tire is initially mounted on wheel rim 42 in a substantially deflated condition permitting the unit to be inserted concentrically within the central opening of trunnion 24 until tire shoulder 50 abuts trunnion shoulder 52. The tire is then inflated by injecting a charge of gas under pressure through valve so that the tire outer surface 46 expands into tightfitting sealing relationship against the inner surface of the trunnion. The tire is locked in this position by insertion of retainer ring 54 which is held in place by mounting retainer rods 56 and plate 58 in the illustrated position. Plastic sealing ring 64 is bolted on mounting flange 66 of the wheel rim with flexible feeder spout 20 positioned to extend through the central opening in the ring. The elements may be easily disassembled by reversing the foregoing procedure, that is, by removing the feeder spout, removing the retainer ring, rod and plate, deflating the tire, and withdrawing the tire and wheel rim from the trunnion opening.

In operation with the elements installed as described, tire 40 is constrained for rotation with the trunnion as shell 12 is rotated by the mill drive. Material to be reduced is introduced into the mill through feeder spout 20 with leakage or spillage from around the spout being precluded by means of close-fitting plastic ring 64. Any distortion of the trunnion due to the load on the elements is accommodated for by the elasticity and resiliency of tire 40. Thus a close-fitting seal is maintained between the tire and inner surface of the trunnion despite this distortion so as to preclude racing between the tire and trunnion. This affords a high degree of protection for the trunnion bearing elements from material leakage. The assembly and disassembly of the elements is simplified in that the tire can be easily deflated and moved into or out of position in the trunnion with a minimum of personnel. The time required for this operation is greatly reduced as compared to existing techniques. Thus, removal of the sealing elements in one mill incorporating the invention takes on the order of 20 minutes as compared to a time of 6 hours required to remove the trunnion liner on conventional equipment of comparable size. Also, the invention makes it feasible to construct mills of greatly increased size due to the simplification of the structure and method of installation for the sealing means. Thus, it is contemplated that ball or tube mills of the type described having a 40' shell diameter and a 10' trunnion diameter could be sealed by means of 9' diameter rubber tire and wheel units of existing design modified in accordance with the present invention.

While the embodiment herein is at present consid ered to be preferred, it will be understood that numerous variations and modifications may be made therein by those skilled in the art and it is intended to cover in the appended claims all such variations and modifications as fall within the true spirit and scope of the invention.

I claim: I p

1. In a mill of the type including a shell supported on trunnions, an in-feed liner and deformable seal comprising a rigid annular rim having an inner circular port for receiving and permitting a feed spout to extend therethrough and means forming an outwardly facing annular recess, an elastomeric annular member constructed of solid material defining a hollow annular chamber having an inwardly facing portion extending about said recess for mounting the same and an outwardly facing cylindrical surface having a diameter commensurate generally with the inner surface of said trunnion, and means for confining a charge of gas under pressure within said member to expand the same to bring said outwardly facing surface into deformable sealing contact with the inner surface of said trunnion.

2. Apparatus for providing a seal between the inner cylindrical surface of a support trunnion on a rotatable shell for a reducing and pulverizing apparatus and a feeder conduit directing infeed material into the shell, the apparatus comprising the combination of a wheel rim positioned co-axially around and in close-spaced relationship with the feeder conduit, an annular inflatable tire mounted around the rim, the tire and rim together defining a chamber for containing gas under pressure, the outer peripheral surface of the tire being mounted against the inner surface of the trunnion whereby gas pressure within the chamber urges the tire outer surface into sealing relationship with the trunmen.

3. Apparatus as in claim 2 in which a liner formed of an elastomeric material is secured to the tire side surface facing the shell.

4. Apparatus as in claim 2 in which an annular liner is secured to the inside surface of the wheel rim, the liner having an inner frusto-conical opening concave toward the shell.

5. Apparatus as in claim 2 in which a sealing ring is mounted within the wheel rim concentric with the feeder conduit and extending inwardly in close-spaced relationship with the feeder conduit.

6. Apparatus for reducing and pulverizing material comprising the combination of a hollow shell for containing a plurality of impacting elements whereby rotation of the shell reduces material progressing through the shell, the shell having an in-feed opening at one end for receiving material to be reduced, bearing means at opposed ends of the shell to support the shell for rotation about its longitudinal axis, the bearing means at the shell end adjacent the in-feed opening comprising a hollow trunnion extending outwardly from the shell and bushing means rotatably supporting said trunnion, feeder conduit means having a discharge end extending concentrically through the trunnion and in discharge relationship with the shell in-feed opening, deformable sealing means for preventing discharge of material from between the trunnion and feeder conduit means, the sealing means comprising an expansible annular member positioned concentrically between the trunnion and feeder conduit means, said annular member having an outer surface adapted to be positioned in sealing relationship with the trunnion and constrained for rotation therewith, the annular member having a central opening positioned in close-spaced relationship around said discharge end of the conduit means and adapted for relative rotation thereto, and means for expanding the annular member radially outwardly.

7. Apparatus as in claim 6 in which the sealing means comprises an annular rigid rim defining said central opening and an annular inflatable tire mounted around the rim, the tire having an outer peripheral surface abutting the inner surface of the trunnion.

8. Apparatus as in claim 7 in which the tire and rim define an annular cavity adapted to be pressurized to radially expand the tire outer surface into sealing relationship with the trunnion, and adapted to be depressurized to contract the tire from the trunnion for dismounting the sealing means.

9. Apparatus as in claim 7 in which the tire is formed of an elastomeric material adapted to accommodate deformation of the trunnion as the shell rotates.

10. Apparatus as in claim 9 in which an annular flexible liner is formed on the tire side surface facing said shell opening and positioned concentrically therewith. 

1. In a mill of the type including a shell supported on trunnions, an in-feed liner and deformable seal comprising a rigid annular rim having an inner circular port for receiving and permitting a feed spout to extend therethrough and means forming an outwardly facing annular recess, an elastomeric annular member constructed of solid material defining a hollow annular chamber having an inwardly facing portion extending about said recess for mounting the same and an outwardly facing cylindrical surface having a diameter commensurate generally with the inner surface of said trunnion, and means for confining a charge of gas under pressure within said member to expand the same to bring said outwardly facing surface into deformable sealing contact with the inner surface of said trunnion.
 2. Apparatus for providing a seal between the inner cylindrical surface of a support trunnion on a rotatable shell for a reducing and pulverizing apparatus and a feeder conduit directing infeed material into the shell, the apparatus comprising the combination of a wheel rim positioned co-axially around and in close-spaced relationship with the feeder conduit, an annular inflatable tire mounted around the rim, the tire and rim together defining a chamber for containing gas under pressure, the outer peripheral surface of the tire being mounted against the inner surface of the trunnion whereby gas pressure within the chamber urges the tire outer surface into sealing relationship with the trunnion.
 3. Apparatus as in claim 2 in which a liner formed of an elastomeric material is secured to the tire side surface facing the shell.
 4. Apparatus as in claim 2 in which an annular liner is secured to the inside surface of the wheel rim, the liner having an inner frusto-conical opening concave toward the shell.
 5. Apparatus as in claim 2 in which a sealing ring is mounted within the wheel rim concentric with the feeder conduit and extending inwardly in close-spaced relationship with the feeder conduit.
 6. Apparatus for reducing and pulverizing material comprising the combination of a hollow shell for containing a plurality of impacting elements whereby rotation of the shell reduces material progressing through the shell, the shell having an in-feEd opening at one end for receiving material to be reduced, bearing means at opposed ends of the shell to support the shell for rotation about its longitudinal axis, the bearing means at the shell end adjacent the in-feed opening comprising a hollow trunnion extending outwardly from the shell and bushing means rotatably supporting said trunnion, feeder conduit means having a discharge end extending concentrically through the trunnion and in discharge relationship with the shell in-feed opening, deformable sealing means for preventing discharge of material from between the trunnion and feeder conduit means, the sealing means comprising an expansible annular member positioned concentrically between the trunnion and feeder conduit means, said annular member having an outer surface adapted to be positioned in sealing relationship with the trunnion and constrained for rotation therewith, the annular member having a central opening positioned in close-spaced relationship around said discharge end of the conduit means and adapted for relative rotation thereto, and means for expanding the annular member radially outwardly.
 7. Apparatus as in claim 6 in which the sealing means comprises an annular rigid rim defining said central opening and an annular inflatable tire mounted around the rim, the tire having an outer peripheral surface abutting the inner surface of the trunnion.
 8. Apparatus as in claim 7 in which the tire and rim define an annular cavity adapted to be pressurized to radially expand the tire outer surface into sealing relationship with the trunnion, and adapted to be depressurized to contract the tire from the trunnion for dismounting the sealing means.
 9. Apparatus as in claim 7 in which the tire is formed of an elastomeric material adapted to accommodate deformation of the trunnion as the shell rotates.
 10. Apparatus as in claim 9 in which an annular flexible liner is formed on the tire side surface facing said shell opening and positioned concentrically therewith. 